A new method for assessing powder flowability based on physical properties and cohesiveness of particles using a small quantity of samples

Characterising powder flowability can be a challenge if only a small quantity of samples is available, e.g. pharma-ceutical formulations. The paper focuses on a new method for assessing powder flowability based on physical properties and cohesiveness of particles using a few grams of powders. The technique applies Bond number to represent powder cohesiveness, which detects particle adhesion at median particle size using a mechanical sur -face energy tester developed at the Wolfson Centre. To establish the method, correlations between the Bond numbers and the flow functions of several powders measured on a shear cell tester have been explored empiri-cally. With the correlations, a prediction model has been developed not only for powder flow functions but also for other flow properties such as compressibility, internal friction angles and true friction angles. This investiga-tion has been undertaken using a wide range of materials from free-flowing to very cohesive for the method es-tablishment and a group of different types of materials for a blind validation of the method. The methodology shows promising results for powder flowability prediction and other flow properties such as compressibility and internal friction angles. The validation results show a good agreement against the results measured using a shear cell tester. (c) 2021 Elsevier B.V. All rights reserved.